[Stoves] Water in coal

[IPC]

Dear Crispin
 
"What is happening now is people are paying for 5 tons of 'Coal' but getting
2 tons of water which they have to buy and trot home in small bags.  Then
they pay for cola to remove it.  Unless it is doing something magical, I
would rather not have poor people pay for water as if it was heat."

Pay for cola? A magical new process?  Or a typo for coal?  

"I can try to remove it." There are two types of moisture in coal, adherent
and inherent.  The adherent can mainly be removed by air drying.  What
remains is inherent, and can only be removed by heating to above 100 degC.
The level of the two types depends partly on the nature of the coal -
younger coals tend to have higher inherent moisture than older coals, so the
brown coals of Eastern Europe are really very wet.  The other thing that
affects moisture is the procesing route - many coals are "cleaned" (have the
ash and sulfur levels reduced) by washing to separate the dense particles.
This leaves the cleaned coal with lots of adherent moisture. The coal can
also be wetted to keep down dust and reduce the risk of spontaneous
combustion when it is stored in heaps - again, high adherent moisture.  So
try some air-drying.  Just be careful of the miners - they tend to say that
if people buy what they have to sell, then the quality is not their problem.
It is often easier to get the customer to say what he or she wants than to
get the miner to change the quality.

Best regards

(Dr)Philip Lloyd
Energy Research Centre
University of Cape Town
Private Bag Rondebosch 7701
South Africa
Tel +27 (0)21 650 3896
Fax +27 (0)21 650 2830